SPECIFICATIONS OF ELECTROLODE II/ELECTROMITE

BACKGROUND

In the photographic process, film having a coating of silver halide is bathed in the solution of fixer or hypo in which the silver compound is dissolved and goes into solution. Silver as it appears in a fixing solution is not in a metallic state, but is part of a negative complex molecule. The estimated loss of silver in the United States from photographic processes is close to one hundred million dollars per year. This loss of silver cannot be permitted to continue for two main reasons ...the depletion of a noble metal, and the pollution of the environment with poisonous silver compounds.

Several methods of silver recovery from hypo have proven successful. These methods include metallic replacement, chemical precipitation, and electrolytic action. Metallic replacement is the principle employed where canister-type units drip used hypo solution through steel wool to achieve a silver for steel metallic exchange. Canisters tend to channel and washout, making them inefficient along with having high costs to refine. The chemical precipitation method consists of adding chemicals and/or metals to used hypo solution to form a sludge of silver sulfide and other compounds which can then be refined to reclaim the silver. This method is difficult to handle and also has high refining costs. The electrolytic process is more efficient and successful. An electrolytic unit which recirculates the fixer solutions, thus reclaiming most silver and saving fixer solution, is the best option.

Problem

A recirulation device which recovers and extends hypo life is not a new invention. Large machines of this type have been in operation in the Kodak and 3M plants for years. They are not only large but very expensive.

The "ELECTROLODE II/ELECTOMITE" is a scale model of the concepts employed by the larger systems. Primary concerns were to collect all available silver, improve film resolution by fixing the film in a silver-free environment, and extend the life of the hypo solution.

A silver recovery machine has to be dependable, economical, and small enough to fit into the usually crowded darkroom. It has to be compatible with all types of machinery used in processing film.

The "ELECTROLODE II/ELECTROMITE" electrolytic unit is engineered to take advantage of the concepts employed in the larger electrolytic machines includes not only design concepts, but exact cathode-to-anode-to-surface relationships, component composition, agitation rate, current density, stable power sources, etc.

The machine must be odor-free, quiet, simple to operate and install, and cannot be allowed to sulfide the hypo bath or cause any other type of possible downtime for the film processor.

TECHNICAL APPLICATION AND FUNCTION

The "ELECTROLODE II/ELECTROMITE" electrolytic unit is a recirculation type of silver recovery device. It connects directly to the film processor in one of two ways. It can be connected directly in line with the processor hypo circulation pump, or it can be connected by hanging polyvinyl tubes over into the hypo tank. It is a sealed unit, i.e., the hypo solution does not cross into contact with air at any point in the process. The machine can act as its own pump since the agitating impeller in the unit is also a pump capable of moving 3 1/2 gallons per minute ...enough to process the entire hypo solution of most x-ray processors every minute

Hypo is circulated to the anode/cathode area where the anode passes a positive charge to the available silver molecules, thus allowing the silver to be electroplated on the negatively charged cathode. The hypo is continuously recirculated to the hypo tank. The silver recovery is continuous -any silver that is missed in the first pass will subsequently be reclaimed due to the recirculation and high agitation of the hypo. The "ELECTROLODE II/ELECTROMITE" electrolytic unit uses high agitation with low amperage, which is necessary for good silver plating and extended life of the hypo.

Agitation is provided by a magnetic drive so that there is no need to use inept seals and bearings that could leak. easier service and removal of the silver Magnetic coupling also facilitates

To service the machine, the cathode assemble can be lifted free of the machine body, thus eliminating the chance of spilling hypo solution onto the electrical components. The cathode assembly is rebuilt each time the silver is removed, eliminating unnecessary downtime.

SUMMARY

The "ELECTROLODE II/ELECTROMITE" electrolytic unit is a well-designed device for silver recovery. In addition, savings of hypo are effected through recirculation. It is compact, economical, and adaptable to service any volume account. Excellent performance characteristics make it the most practical means of saving silver and hypo plus the added convenience and clean operation. As the ecology laws are strengthened, it will soon be necessary for all developers of photographic film to update their systems of silver recovery. The "ELECTROLODE II/ELECTROMITE" electrolytic unit, by removing the contaminate silver bromide from the solution, greatly reduces the pollution danger and should comply with any requirements.